CHROMIUM NITRIDE COATING FILM BY ION PLATING, PROCESS FOR PRODUCING THE SAME, AND PISTON RING FOR INTERNAL COMBUSTION ENGINE

摘要

A coating film improved in the property of being hard but apt to chip, which is inherent in chromium nitride coating films deposited by ion plating. The coating film is excellent in wearing resistance and seizing resistance, the level of which is required to increase more and more in diesel engines. It further has excellent unsusceptibility to chipping. The coating film has the following properties. Composition: chromium, nitrogen, and carbon are major components and the carbon concentration is 4-8 wt.% based on the total concentration of these major components. Crystal structure: the crystal orientation of the CrN (111) plane is 0.4-2.0in terms of CrN (111) structure coefficient. Hardness: Hv1,600-Hv2,000.